The present invention concerns a rain sensor, particularly for watering systems.
For the maintenance of lawns, gardens, kitchen gardens and other cultivated spaces the use of automatic watering systems controlled by an electronic programmable central unit is increasingly widespread. This allows to guarantee the correct watering also in the absence of the operator of the system, as it usually happens for holiday houses.
Naturally it is completely useless for the central unit to start the watering system during rainy days, when the rain water is more than sufficient to guarantee the cultivations the desired degree of humidity.
Therefore, modern watering systems utilise rain sensors that, when the same rain exceeds a certain pre-established limit, send the central unit an electric signal that is capable to prevent the starting of the system or, if already operating, to control its setting to rest.
A suitable rain sensor must naturally not only be able to collect the rain and to signal the attainment of the pre-established limit but also to reset itself to zero as quick as possible when the rain stops, in order to restore the start of the system and be ready for a correct indication at the following rain. In addition it must guarantee a suitable protection against the introduction of foreign matters that could spoil to the correctness of the measurement and even put it out of use.
Having considered that, it is an object of the present invention to provide a rain sensor that would offer the maximum guarantees for a good operation.
According to the invention such object has been reached with a rain sensor characterized in that it comprises a tray for the collection of rain water provided on top with side evaporation and overflow windows, a perforated cover placed as a cover of said tray, a finned float housed in said tray so as to be able to move vertically as a function of the level of the water present in the tray, a permanent magnet supported by said float and an electric magneto-sensitive switch that is fixed to the tray and is switchable between a first and a second electric state as a function of the vertical position of the float.